A variety of systems require the ability to track an object in three-dimensional space and to translate the position of the object into data which can be used by a computer system. One example of such an application is the tracking of the head position of a user of a virtual display system. In a virtual display system, an image is transmitted to a user which changes according to the field of view the user would ordinarily have if the virtual display system was not present. The virtual display system may be used, for example, to relay information to a pilot of an aircraft. The head position of the pilot must be tracked and translated into computer readable data in order for the virtual display system to function.
Present systems use electromagnetic coils coupled to the helmet of the pilot to achieve this head-tracking capability. These electromagnetic systems have several disadvantages. First, the electromagnetic environment of the cockpit produces a large amount of noise which interferes with the operation of the system. Further, the electromagnetic systems are very susceptible to possibly debilitating interference from an electromagnetic pulse resulting from a nuclear blast. An important concern in the design of virtual display systems used in warfare applications is to insure functionality of a system in such adverse conditions.
Accordingly, a need has arisen for a device for tracking an object in three-dimensional space and for translating the position of that object into a computer readable form. A further need has arisen for a tracking system which can operate efficiently in an environment having a great deal of electromagnetic interference.